The invention relates to a transverse conveyor for conveying of pin-shaped workpieces on machines having a plurality of working stations. The stations may be arranged in a vertical plane, such as, for example, on multiple-step presses. The transverse conveyor has tong-shaped gripper arms, the arms being mounted to execute a transverse movement in order to pass the workpiece from one processing station to the next. A back movement is provided for the return of empty gripper-arms. The arms also execute closing and opening movements for gripping and releasing the workpieces.
Transverse conveyor devices for multistep presses are known. In one known device, a plurality of gripper pairs are mounted on a carrier plate to have a translatory movement between processing steps. This results in large mass moments of inertia, leading to great wear of the movable parts. Precision in the setting of the final positions of the device can be obtained only within limits, so that the overall efficiency of the device is impaired.
In some known transverse conveyor devices, this disadvantage of large moments of inertia is prevented by an arrangement employing a plurality of coupled pivotable levers. In this arrangement, though it is not possible to use the well known transverse conveyor tongs having gripper-arms that open and close at periodically repeating time intervals. Such gripper-arms are operated by a motion control mechanism and the opening and closing movements of both gripper-arms of each set are intercoupled. This arrangement is described, for example, in DE-OS No. 2,813,108.
The above conveyor devices have rigid gripper-arms which can only perform a kind of "snapping function". This is disclosed in DE-OS No. 2,148,529, DE-AS No. 1,272,687, DE-AS No. 1,271,516 and U.S. Pat. No. 3,022,526.
The above transverse conveyor devices are limited for use only with parts that correspond to the construction of the conveyor means. The output of the multistep press is mainly a function of the potential efficiency of the grippers. It is impossible to make the above described transverse conveyor device dependent on the rhythm of the press process, and the gripper-parts are subject to extraordinary wear.
Prior solutions, having a combination of an arrangement with low inertia forces and enabling forced opening and closing of the gripper pairs, are so complicated that a greater output cannot be obtained. The transport of workpieces, which up to now use a fraction of the time needed for a turn of a crankshaft, is a characteristic criterium for the increase of the number of press cycles and for improved utilization of multistep presses.